Note that I've encountered some mysterious errors using django.contrib.gis.
String or unicode input unrecognized as WKT EWKT, and HEXEWKB.
An error that occurs when converting a String or Unicode object to a GEOS object such as Point or Polygon, if the conversion fails. If you are using GeoJSON, GDAL is required to convert the object.
django.contrib.gis.geos.error.GEOSException: Could not parse version info string "3.4.2-CAPI-1.8.2 r3921"
Occurs when Django and GEOS versions are unmatched (at hand, it happens with a combination of Django 1.4 + GEOS 3.4.2). In stackoverflow, an example of patching django to avoid it is introduced.